Superregenerative receiver



y 1933- t c. A. GUNTHER 1,917,113

SUPERREGENERATIVE RECEIVER Filed April 28, 1932 A +A +3 osc.

Inventor: C l arence AG unther',

His Attorney 16 is composed of an iron-cored inductor 17 having a tuningcapacitor 18 in parallel therewith. A radio frequency choke 19 isconnected in the grid circuit between the grid element of the oscillatordischarge device 20 and the inductor 17. The anode circuit of theelectron discharge device 20 is provided with an inductor 21 whichisarranged in an inductive relation to the inductor 17 to permit thecircuit to oscillate. The electron discharge device 20 of the oscillatorcircuit 16 is connected across the input circuit of the electrondischarge detector 6 by means of a capacitor 22 arranged between thegrid element of the oscillator discharge device 20 and the gridcondenser 4 of the electron dis charge detector 6, and the connectionbetween the cathodes of the electron discharge devices 6 and 20. Theimpedance coupling member or capacitor 22 is of such value in comparisonwith the, capacitor 18 of the oscillator circuit that the desiredfrequency of the oscillations in the oscillator 16 is not disturbed. Theradio frequency choke 19 is of a value presenting a high impedance tothe ultrahigh frequency energy present in the input circuit of thedetector 6 but also presenting a low impedance to the frequencygenerated by the oscillations of the oscillator discharge device 20.

A variable resistor 23 is connected in the common return of the cathodesof discharge devices 6, 13 and 20 to provide a means for controlling thetemperature of the cathodes. In the output circuit of the detector 6, Ihave arranged a filter 25 for reducing undesired frquencies such asthose which comprise the background noise. This filter, while notessential to the operation of the super-regenerative detector. is adesirable feature, and is composed of an inductor 26. a resistor 27, asecond resistor 28 and. an iron-cored inductor 29 in series with theprimary winding 30 of an output device 31. A plurality of capacitors 32,33 and 34-. are connected respectively between the elements 26 and 27,28 and 29, 29 and 30 and the common return connection 35 whichisconnected to the cathodes of the electron diseh arge devices 6, 13 and20. A capac: itor 36 in series with an iron-cored inductor 37 isconnected between the common return connection 35 and a point betweenthe resistors 27' and 28. A capacitor 38 is connected between the returnconductor 35 and the conductor 39 which is connected to one terminal ofthe primary winding 30 of the output device 31. A variable resistor 40is arranged between a suitable source of potential' for the anode ofdetector 6 and the conductor 39 for the purpose of providing a controlof the potential applied to the anode of the detector 6. The secondaryWinding 41 of the output device 31 be connected toan audio frequencyamplifier or a suitable translating device.

means of the resistor 40 so that normally sustained oscillations arepresent in themput circuit of the detector 6 and the audible frequencyintroduced by the oscillator 16 is present in the output only when acarrier wave is being received. lVith this ad ustment, an audiofrequency will be present in the output only at the time when continuouswave signals are being received.

The super-regenerative action is introduced into the. detector 6by'meansof, the action of the electron discharge devices 13 and 20operating in accordance with the frequencies generated by theoscillators 9 and 16. The incoming ultra high frequency signals whichare of the continuous wave variety are modulated by the audiblefrequency generated by the oscillator 16 to provide a signal in theoutput circuit of the detector having a constant audio frequency,regardless of the frequency of theincoming signals or any variationtherein. The signals produced in the output circuit of the de tector 6remain at a constant frequency regardless of any variations of thedetector circuit variables as long as the frequency of the oscillator 16is not altered.

It has been found that a certain relation erative action resultinginoptimum opera-v tion. For ultrahigh frequency reception, the audiofrequency suppliedby a source such as the oscillator 16 would be too loWfor proper super-regenerative action. To supply the proper frequency forsuch optimum operation, the oscillator 9 is provided in addition to theoscillator 16 ,Whiehprovides the necessary audio frequency component forthe modulation of the signals. To obtain this desideratum in theoperation of the receiver, the oscillator 9:is tuned so that the effectproduced by the combined action of the two electron discharge devices 13and 20 is such that the greatest sensitivity is obtained. The combineduse of the electron discharge devices 13 and 20 results ina greatergain, greater ease in tuning and less critical adjustment of thecomponent parts of the apparatus than would'be the case if the properfrequency were not obtained.

' In operation, the electron discharge devices13 and 20 operate toperiodically suppress the normally-sustained oscillations present in theinput circuit of the detector 6, thereby varying the degree ofregeneration present. These electron discharge devices 13 and 20 areenabled to perform this funclation generators for preventing the highfrequency signal energy in said detector in put circuit from. enteringsaid oscillation generators and for causing said oscillation generatordischarge devices periodically to suppress said normally-sustainedoscillations thereby to produce simultaneously a super-regenerativedetector action and modudetector action, and means connected to said.

grid element and included in said oscillation generator circuit to causesaid grid element periodically to draw current having a steep wave frontform, said means also serving to isolate said oscillation generatorelements from said regenerative detector circuit.

5. In a high frequency radio receiving system, the combination of anelectron discharge detector arranged in a circuit to producenormally-sustained oscillations in said circuit at the signal frequency,means for collecting high "frequency signal energy and for impressingsaid energy upon said detector circuit, an electron discharge deviceincluding a grid element and a cathode arranged in a circuit to generatehigh frequency oscillations, means for coupling said grid element andsaid cathode to said detector circuit, whereby said electron dischargedevice periodically suppresses said normally-sustained oscillation toproduce a super-regenerative' detector action, and means connected tosaid grid element and included in said oscillation generator circuit tomaintain at all times a high external impedance between said-element andsaid cathode, said means also serving to prevent high frequency signalenergy from entering the oscillation generator cir-' cuit. i V

6. A regenerative receiving circuit having an input circuit, saidregenerative receiving circuit being arrangedto producenormallysustained'oscillations, a plurality of electron dischargedevices arranged in oscillatory circuits, each of said discharge deviceshaving a grid element and a cathode, means for maintaining the externalgrid-to-cathode circuit impedance of said discharge devices high at alltimes and for causing the internal grid-

